Polymer co-networks can serve as a means to encapsulate and thereby immunoisolate implantable biologically active moieties. Generally, polymer co-networks comprise hydrophilic and hydrophobic polymers that can swell in both polar and non-polar solvents.
Additionally, polymer networks and/or co-networks can be used to produce polymer films that swell in both polar and non-polar solvents. Accordingly, films made from polymer networks and/or co-networks have been found to be desirable in the production of contact lenses.
One problem associated with the synthesis of polymer, or copolymer, networks is how to overcome the thermodynamic incompatibility of the hydrophilic and hydrophobic constituents that will make up the network, and to unite two incompatible pre-polymers and/or polymers into a bi-continuous/bi-percolating construct. Typically, crosslinking of such systems is carried out in homogeneous solution in a common solvent at low pre-polymer and/or polymer concentrations, followed by the addition of a suitable crosslinker (i.e., by dissolving the two pre-polymers which are generally incompatible in their dry states). While this method yields uniform co-networks, the removal of the common solvent is accompanied by massive shrinkage, which renders the method technically impractical. Also, the dimensional stability of such networks, or co-networks, is poor, the surface properties are hard to control, and the networks, or co-networks, (or products formed therefrom) are fragile and difficult to manipulate.
Thus, there is a need in the art for reliable synthesis routes for polymer networks, or co-networks. Specifically, desirable synthesis routes would include those that permit the control of one or more chemical and/or physical properties of a polymer network, or co-network. Also of interest are synthesis routes for polymer networks, or co-networks, that produce networks that are suitable for use in medical (e.g., cell encapsulation), biological and ophthalmic uses.